zram: fix out-of-bounds access in writeback_store()
In the Linux kernel, the following vulnerability has been resolved: zram: fix out-of-bounds access in writeback_store() Patch series "zram: fix stale scan bounds after reinitialization". Both writeback_store() and read_block_state() derive their table scan bounds from zram->disksize before acquiring dev_lock. If the device is reset and reinitialized with a smaller disksize between that read and lock acquisition, the bound can describe the old table while the scan operates on the new one. This can lead to out-of-bounds slot accesses. Move both bound calculations under dev_lock so each bound remains consistent with the table throughout its scan. Keep the fixes separate because the affected interfaces originate from different commits and can be backported independently. This patch (of 2): writeback_store() calculates the table scan bounds before taking dev_lock. A reset followed by reconfiguration with a smaller disksize can therefore replace zram->table while writeback_store() is waiting for the lock. Once it acquires the lock, it sees an initialized device but scans the new table using the old upper bound, resulting in an out-of-bounds access. Calculate the number of pages while holding dev_lock so the scan bound matches the table protected by the lock.
- Published
- Sep 11, 2026
- Updated
- Sep 21, 2026
- EPSS
- 0.2% · 10th percentile
- CWE
- —
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Report tools
Action score
0
Monitor
Low priority for now.
- CVSS
- 0 / 40 · —
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
Affected systems
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Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 5.0affected
- a939888ec38bf1f33e4a903056677e92a4844244 and later · before 4d82d60178b02797dbe529e01ac211b26670c49faffected · git
- a939888ec38bf1f33e4a903056677e92a4844244 and later · before 07a82a66f8c1894d92e51d97542c32ebf2c51b09affected · git
- a939888ec38bf1f33e4a903056677e92a4844244 and later · before 894913e2d35c46ff19a77530907771ae57862b96affected · git
- before 5.0not affected · semver
- 6.12.111 and later · up to and including 6.12.*not affected · semver
- 7.2.4 and later · up to and including 7.2.*not affected · semver
- 7.3-rc1 and laternot affected · original_commit_for_fix
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | all versions | — |
| Debian:13 | linux | before 6.12.111-1 | 6.12.111-1 |
| Debian:14 | linux | before 7.2.6-1 | 7.2.6-1 |
Same product
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Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 07a82a66f8c1894d92e51d97542c32ebf2c51b09 | Vendor (CNA) |
| Linux Linux | 4d82d60178b02797dbe529e01ac211b26670c49f | Vendor (CNA) |
| Linux Linux | 894913e2d35c46ff19a77530907771ae57862b96 | Vendor (CNA) |
| debian:linux | 6.12.111-1 · Debian:13 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
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No commit or PR link among the references.
Credits
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No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
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Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
No CVSS vector for this record, so attack conditions can't be derived.
Weakness class (CWE)
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Attack context
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Noroxi analysis
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References
- git.kernel.org/stable/c/07a82a66f8c1894d92e51d97542c32ebf2c51b09
- git.kernel.org/stable/c/4d82d60178b02797dbe529e01ac211b26670c49f
- git.kernel.org/stable/c/894913e2d35c46ff19a77530907771ae57862b96
Vendor advisories and official records. Exploit/PoC links are deliberately left out.